Objective: Many individuals who encounter potentially traumatic events go on to develop post-traumatic stress disorder (PTSD) symptoms. Research suggests that survivors of traumatic events frequently compare their current well-being to different standards. Yet, our understanding of the role of comparative thinking in well-being is limited to a few cross-sectional studies. We therefore examined the temporal relationship between aversive well-being comparisons (i.e., comparisons threatening self-motives), PTSD symptoms, and life satisfaction in individuals with a trauma history. Method: A sample of 518 participants with exposure to traumatic events was administered measures of PTSD, life satisfaction, and the Comparison Standards Scale for Well-being (CSS-W) at two timepoints, three months apart. The CSS-W assessed the frequency, perceived discrepancy, and affective impact of aversive social, temporal, counterfactual, and criteria-based comparisons related to well-being. Results: Comparison frequency emerged as significant predictor of PTSD symptoms, beyond baseline PTSD levels. Life satisfaction contributed unique variance to the comparison process by predicting comparison frequency, discrepancy, and affective impact. The findings suggest that frequent aversive comparisons may lead to a persistent focus on negative aspects of well-being, thereby exacerbating PTSD symptoms. They further indicate that comparison frequency, discrepancy, and affective impact are significantly influenced by life-satisfaction. Conclusions: Altogether, the findings support the need for a thorough examination of the role of comparative behavior in clinical populations, which may ultimately help improve clinical care.